The cookies: Sift the almond flour, the confectioners' sugar and the cocoa.Beat the egg whites with the salt with an electric mixer on medium-high speed in a large bowl until the whites form soft peaks. Add the granulated sugar and beat until the whites form stiff and glossy peaks. Gently fold in the almond mixture with a rubber spatula.

Transfer the batter to a pastry bag fitted with a 1/2-inch plain tip. Pipe out 1-inch-diameter mounds about 2 inches apart on baking sheets with baking paper.

Bake, one sheet at a time: Put the baking sheet in the hot oven (360 degrees F) and turn down the heat to 285 degrees (140 C). Bake 12-15 minutes, until the tops are cracked and appear dry. Repeat with remaining baking sheets/cookies.

Let the cookies cool for 5 minutes and transfer them to a wire rack to cool completely.

The filling: Bring the cream to a boil in a saucepan over high heat. Remove the pan from the heat and add the chocolate. Whisk until smooth, let cool to room temperature and then refrigerate, covered until the filling is firm enough to hold its shape.

Spread the chocolate filling on the flat side of half of the macarons. Top with the remaining macarons, flat-side down, pressing together gently to form sandwiches.The macarons can be stored in an airtight container in the refrigerator for up to 2 days.